Key trap

ABSTRACT

A key trap lock structure, which is designed to be operated so that outstanding keys, desired to be retrieved by building personnel, can be trapped in the lock after insertion and prior to intended door opening. The lock is designed such that the central bolt or cylinder member, upon being rotated by key through a predetermined arc, will, by it&#39;&#39;s catch element springing outwardly, engage a slot in the housing so that the cylinder member cannot be turned and the key cannot be retrieved. Thus, the unauthorized user must leave the key in the lock. Subsequently, maintenance or building personnel, by the means shown, can reload the catch element so that the cylinder member can be turned to the original position for insertion. Thereafter, appropriate means can be installed to retain the catch element in the non-catch, lock-operative position.

United States Patent [191 Austin et al.

[451 Sept. 23, 1975 KEY TRAP Inventors: Keith L. Austin, 4620 Brown St.,

Murray, Utah 84107; Harper K. Morris, 221 l Karo, Idaho Falls, Idaho 83401 Sept. 21, 1973 Primary E.\'aminerRoy D, Frazier Assistant ExaminerPeter A. Aschenbrenner [57] ABSTRACT A key trap lock structure. which is designed to be operated so that outstanding keys, desired to be retrieved by building personnel, can be trapped in the lock after insertion and prior to intended door opening. The lock is designed such that the central bolt or cylinder member, upon being rotated by key through a predetermined arc, will, by its catch element springing outwardly, engage a slot in the housing so that the cylinder member cannot be turned and the key cannot be retrieved. Thus, the unauthorized user must leave the key in the lock. Subsequently, maintenance or building personnel, by the means shown, can reload the catch element so that the cylinder member can be turned to the original position for insertion/Thereafter, appropriate means can be installed to retain the catch element in the non-catch, lock-operative positron.

10 Claims, 7 Drawing Figures US Pagent Sept. 23,1975

FIG.5

FIG. 4A

308 FIG. 5A

KEY TRAP The present invention relates to lock mechanisms, and more particularly, to a new and improved lock mechanism which can be set to retain or trap the key of an unauthorized person.

The central concept of the invention is to provide a sleeve which can be keyed to a door or remaining lock structure, and a bolt or cylindrical member rotationally displaceable in such sleeve. The structure is designed to have a catch element which, upon partial rotation of the cylinder member relative to the sleeve, will effectively releasably connect the two together so that further rotation is impossible. Yet, the key will remain trapped in the cylinder member by virtue of springloaded pin means engaging the undulating surface of the key and the catch element employed preventing return of the cylinder member to its original position.

Advantageously, a small hole and pin or needle may be used to reset the catch element so that the cylinder member may be rotated back to the original, key insertion position. An elongate screw resembling a jewelers screw can also be employed to releasably retrieve the catch element for normal lock usage. Such. screw will be removed only at times when it is desired to trap outstanding, unauthorized keys.

Accordingly, a principal object of the present invention is to provide a new and improved key trap structure.

An additional object is to provide a key trap lock structure which can be conditioned to retain inserted, unauthorized keys within the lock structure before such lock structure is effective to unlatch or unlock a door.

An atirllitional object is to provide pivotable catch element means between the cylinder member and sleeve or the lock structure, the former being spring loaded to fall into provided slot means so as to freeze the bolt or cyli'nder member relative to its sleeve at a predetermined point of rotation of the cylinder member relative to such sleeve.

The features of the present invention may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a side elevation of the sleeve and cylinder member incorporated in the present invention.

FIG. 2 is a front elevation of the structure or FIG. 1 and is taken from a view to the right of FIG. 1.

FIG. 3 is an enlarged, longitudinal, vertical section taken on the line 33 FIG. 2.

FIG. 4 is an enlarged section taken along the line 44 in FIG. 1.

FIG. 4A is a view similar to FIG. 4, but illustrates the structure with the key and the cylinder member having been turned, and with the catch element engaging the sleeve slot.

FIG. 5 is a plan view of the structure of FIG. 1, is partially broken away to show the lock catch element and the lock needle urging the same to the retrieved position.

FIG. 5A is a fragmentary section view similar to the upper portion of FIG. 5, but illustrates an elongated jewelers screw as being installed to retain the catch element in its retrieved position.

In FIGS. l-3 and FIG. 5 the invention is shown to include a conventional lock sleeve having an alignment fin portion 1 l integral with sleeve portion 12. Fin

portion 11 is shown to be provided with plural interior apertures 13, 14, and 15 each of which includes a bottomed, respective spring 16, 17, and 18 which operate as compression springs for base pins 19, 20, and 21. When the key 37 is inserted as in FIG. 3, the upper surfaces of base pins 19-21 respectively define a shear plane 23. This plane is actually a cylindrical surface which, with the necessary end alignment of detent pins 24, 25, and 26, as the same pressure engage key 37 will enable the cylinder member 27 to revolve within sleeve portion 12. Of importance with respect to bolt or cylindrical member 27 is inclusion of a slot 28 and aperture 29 which accommodate the positionment of pivotal catch element 30 and catch element pivot pin 31, respectively. It is seen in FIGS. 3 and 5 that the catch element 30 has a general L-configurement, having reaction, actuation arm 30A and lock arm 30B, and includes as a biasing member the compression spring 32 which is seated against arm 30A of the catch element and also against the springs seat 33 in the rotating cylinder member 27.

correspondingly, there is provided in sleeve portion 12 a slot 34 which is designed for the reception of catch element 30 when the same is disposed in the dotted-line position as at 30 in FIG. 5.

FIG. 4 illustrates that, relative to key slot 36, it is preferred that catch element 30 be disposed in essentially a relationship relative to the key slot. At least, slot 34 should be transversely positioned such that the door does not unlock even though the key is turned partially, i.e., 90 so as to bring catch element 30 in alignment with slot 34 and thereby permit the former to spring upwardly to assume its dotted line configuration 30' in FIG. 5.

It will be understood that when the key 37, shown in FIGS. 3 and 4, is removed, the pins 24-26 will spring upwardly under the pressure of compression springs 16-18 and their base pins 19-21 so that the cylindrical shear plane 23 will be broken, thereby precluding further revolvement of cylindrical member 27 relative to sleeve 10 until the key is replaced, see FIG. 4A.

To complete the structure there will be provided a threaded extremity 39 for cylinder member 27 which cooperates with the interior threads 40 of cap 41. Cap 41 is useful to retain a disk-like, interiorly slotted retainer 42, the latter being of conventional design, found in conventional lock pieces, and tailing or mounting the tail piece 43. Tail piece 43 is of the usual form and includes appropriate conventional linkage or structure 44 to actuate bolt or latch 45. All of this is conventional Of importance in the construction of cylinder member 27 is the inclusion of bore 47. The same receives an elongate jewelers screw 48, see FIG. 5A, having a threaded extremity 49 threading into threaded portion 50 of the bore. Screw 48 will be used to maintain the catch element 30 in its retrieved orientation as shown in solid lines as in FIG. 5.

In operation, should the user wish to catch or trap a key within this particular lock, he will remove the screw 48. Catch element 30 will still be retained in its solidline condition, by the inner wall surface of sleeve position 12, until a key 37 is inserted and the bolt or cylinder rotationally displaced such that catch element 30 comes in alignment with slot 34. At this point the catch element 30, under the spring pressure of spring 32, will spring outwardly such that, of the catch elements arms 30A and 30B, arm 30B will engage the slot. At this point the cylinder member will not be able to be rotated further or even in either direction within the sleeve portion 12. And yet the detent pins 24-26 will prevent the key from being pulled outwardly. Thus, the key is literally trapped In order for the custodian to retrieve this key, he will merely insert a release needle 51 in lieu of the previously removed jewelers screw 48. This release needle will serve to engage the catch so as to return it to its solid line configuration as shown in FIG. 5; at the same time the cylinder member will be returned to its original position so that the key can be removed.

It is noted that the operation of the equipment centers upon the pivotal movement of catch element 30 within its slot 28 of cylinder member 27. The positioning of catch element 30 and slot 34, of course, can be reversed.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art the various changes and modifications which may be made without departing from the essential features of the present invention and, therefore, the aim in the appended claims is to cover all such changes and modifications, as fall within the true spirit and scope of the invention We claim: 7

I 1. In a lock mechanism, in combination, a revolvable cylinder mcmber having a key slot; asleeve member having a cylindrical sleeve portion journalling said cylinder memberv and means for fixedly retaining said sleeve portion in a fixed disposition; spring-biased catch means, pivoted for movement in a longitudinal plane with respect to said cylinder member, for releas ably locking said cylinder member to said sleeve portion when the former is rotationally displaced relative to the lattcra predetermined degree from key-insertion disposition, said sleeve and said cylinder member each including mutually spaced, respectively aligned, radially oriented pin bores; plural key-detent pins operatively disposed in said cylinder member bores; springbiased base pins respectively disposed in said sleeve bores and engaging said key-detent pins, at said keyinsertion disposition, along the arcuate juncture defined by said cylinder member and said sleeve portion;

and means for enabling the retrieval of said catch means.

2. Apparatus according to claim 1 wherein said sleeve portion includes a wall slot, said catch means being pivoted to said cylindrical member proximate the latters transverse periphery in being alignable with and, when in alignment, engagcable with said slot.

3. Apparatus according to claim 1 wherein said fixedly retaining means comprises an outwardly, radially extending positioning fin.

4. Apparatus according to claim 1 wherein said catch means is dimensioned and positioned for locking said cylinder member to said sleeve portion prior to lockmechanism opening.

5. Apparatus according to claim 1 wherein said cylinder member includes an aperture parallel to the axis of said cylinder member and .aligned with said catch means, whereby an external implement may be inserted through said aperture to engage said catch means and thereby retrieve the entirety of the same within said sleeve portion. 6. Apparatus according to claim 1 wherein said lock mechanism includes an elongate screw threadedly engaging said aperture and abutting said catch means against the latters springbias'when in retrieved position.

7. Apparatus according to claim 1 wherein said catch means comprises a lever having a lock arm and a reaction, actuation arm angularly disposed relative to said lock arm. i

I 8. Apparatus according to claim 1 wherein said'catch means is L-eonfigured.

9. Apparatus according to claim 1 wherein said mechanism includes a tail piece, a'disc-configured slotted retainer receiving said tail piece, and cap means threaded onto said cylinder member for releasably retaining said retainer against said cylinder member.

10.Apparatus according to claim 1' wherein said catch means includes a'pi'vot member transversely secured to said cylinder member, said cylinder member including a slot operatively receiving said catch means. 

1. In a lock mechanism, in combination, a revolvable cylinder member having a key slot; a sleeve member having a cylindrical sleeve portion journalling said cylinder member and means for fixedly retaining said sleeve portion in a fixed disposition; spring-biased catch means, pivoted for movement in a longitudinal plane with respect to said cylinder member, for releasably locking said cylinder member to said sleeve portion when the former is rotationally displaced relative to the latter a predetermined degree from key-insertion disposition, said sleeve and said cylinder member each including mutually spaced, respectively aligned, radially oriented pin bores; plural keydetent pins operatively disposed in said cylinder member bores; spring-biased base pins respectively disposed in said sleeve bores and engaging said key-detent pins, at said key-insertion disposition, along the arcuate juncture defined by said cylinder member and said sleeve portion; and means for enabling the retrieval of said catch means.
 2. Apparatus according to claim 1 wherein said sleeve portion includes a wall slot, said catch means being pivoted to said cylindrical member proximate the latter''s transverse periphery in being alignable with and, when in alignment, engageable with said slot.
 3. Apparatus according to claim 1 wherein said fixedly retaining means comprises an outwardly, radially extending positioning fin.
 4. Apparatus according to claim 1 wherein said catch means is dimensioned and positioned for locking said cylinder member to said sleeve portion prior to lock-mechanism opening.
 5. Apparatus according to claim 1 wherein said cylinder member includes an aperture parallel to the axis of said cylinder member and aligned with said catch means, whereby an external implement may be inserted through said aperture to engage said catch means and thereby retrieve the entirety of the same within said sleeve portion.
 6. Apparatus according to claim 1 wherein said lock mechanism includes an elongate screw threadedly engaging said aperture and abutting said catch means against the latter''s springbias when in retrieved position.
 7. Apparatus according to claim 1 wherein said catch means comprises a lever having a lock arm and a reaction, actuation arm angularly disposed relative to said lock arm.
 8. Apparatus according to claim 1 wherein said catch means is L-cOnfigured.
 9. Apparatus according to claim 1 wherein said mechanism includes a tail piece, a disc-configured slotted retainer receiving said tail piece, and cap means threaded onto said cylinder member for releasably retaining said retainer against said cylinder member.
 10. Apparatus according to claim 1 wherein said catch means includes a pivot member transversely secured to said cylinder member, said cylinder member including a slot operatively receiving said catch means. 